Metropolitan Police Commissioner Sir John Stevens has been made a life peer on the day he retires.
Sir John said the peerage was a great honour
The non-political peerage, announced on Sir John's last official day in the job, was granted on the recommendation of Prime Minister Tony Blair.
Sir John said: "I am grateful to the Queen and prime minister for conferring this great honour on me."
On Tuesday, the 62-year-old will be succeeded by his current deputy, Sir Ian Blair.
Sir John said the peerage reflected the support of his family, friends and colleagues in the Met.
"Without them this would not have been possible," he said.
He will continue to head the inquiry into the death of Diana, Princess of Wales, after his retirement.
At his final public appearance on Friday, Sir John attended a passing out parade of London's latest police recruits in Hendon.
Sir John, considered a "copper's copper", said he was immensely sad to leave his police job after 43 years. He had been the commissioner for five years.
Sir Ian's first day in the job is likely to combine public engagements with briefing his officers and interviews with the media.
Sir John said his replacement would have to have "a massive amount of resilience which he has, and a passion for policing, which I'm sure he's got".